diff --git a/README.md b/README.md
index a5385b5..ba9dff1 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@ Enjoy!
 
 ##  What remains to be done
 
+- Filter saving PGN to 80 characters per line
 - Finish Zobrist hashing unit test with all the scenarios: castling, attack, etc.
 - Ensure that when a Game is copied, the history is also copied, not just referenced because it will get messed up (see FEngineInfo)
 - Better handling of openings when a FEN is passed (and the board is not in the expected state for the opening)
@@ -31,3 +32,10 @@ Enjoy!
 - Add more openings
 - Transposition table [here](http://www.chessbin.com/post/Transposition-Table-and-Zobrist-Hashing) and [here](https://chessprogramming.wikispaces.com/Transposition+Table)
 - [Optimization](https://people.cs.clemson.edu/~dhouse/courses/405/papers/optimize.pdf)
+
+## Limitations
+
+- unable to have read-only document (it always want to write it back)
+- background of List is not transparent in Light Mode (it is white)
+- unable to create rich text with support of tapping in it (like to select precisely the white or black move)
+
diff --git a/Shared/BChessUIApp.swift b/Shared/BChessUIApp.swift
index feacf4b..0825d1d 100644
--- a/Shared/BChessUIApp.swift
+++ b/Shared/BChessUIApp.swift
@@ -11,7 +11,7 @@ import SwiftUI
 @main
 struct BChessUIApp: App {
     var body: some Scene {
-        DocumentGroup(newDocument: ChessDocument()) { file in            
+        DocumentGroup(newDocument: try! ChessDocument()) { file in            
             ContentView(document: file.$document)
         }
         #if os(macOS)
diff --git a/Shared/ChessDocument.swift b/Shared/ChessDocument.swift
index c5e1161..057f47f 100644
--- a/Shared/ChessDocument.swift
+++ b/Shared/ChessDocument.swift
@@ -111,9 +111,11 @@ struct ChessDocument: FileDocument {
         return PiecesFactory().pieces(forState: engine.state)
     }
     
-    init(pgn: String = startPosPGN, white: GamePlayer? = nil, black: GamePlayer? = nil, rotated: Bool = false, mode: GameMode = GameMode(value: .play)) {
+    init(pgn: String = startPosPGN, white: GamePlayer? = nil, black: GamePlayer? = nil, rotated: Bool = false, mode: GameMode = GameMode(value: .play)) throws {
         self.pgn = pgn
-        self.engine.loadAllGames(pgn)
+        guard self.engine.loadAllGames(pgn) else {
+            throw CocoaError(.fileReadCorruptFile)
+        }
         self.whitePlayer = white ?? GamePlayer(name: "", computer: false, level: 0)
         self.blackPlayer = black ?? GamePlayer(name: "", computer: true, level: 0)
         self.rotated = rotated
@@ -146,9 +148,9 @@ struct ChessDocument: FileDocument {
             let decoder = JSONDecoder()
             let state = try decoder.decode(GameState.self, from: data)
 
-            self.init(pgn: state.pgn, white: state.white, black: state.black, rotated: state.rotated)
+            try self.init(pgn: state.pgn, white: state.white, black: state.black, rotated: state.rotated)
         } else if configuration.contentType == .pgn {
-            self.init(pgn: String(decoding: data, as: UTF8.self),
+            try self.init(pgn: String(decoding: data, as: UTF8.self),
                       white: GamePlayer(name: "", computer: false, level: 0),
                       black: GamePlayer(name: "", computer: false, level: 0))
         } else {
diff --git a/Shared/Views/BoardView.swift b/Shared/Views/BoardView.swift
index 68e7117..0527cb3 100644
--- a/Shared/Views/BoardView.swift
+++ b/Shared/Views/BoardView.swift
@@ -43,7 +43,7 @@ struct BoardView: View {
 
 struct BoardView_Previews: PreviewProvider {
     static var previews: some View {
-        let doc = ChessDocument()
+        let doc = try! ChessDocument()
         BoardView(document: .constant(doc))
     }
 }
diff --git a/Shared/Views/ContentView.swift b/Shared/Views/ContentView.swift
index abba323..ac2235b 100644
--- a/Shared/Views/ContentView.swift
+++ b/Shared/Views/ContentView.swift
@@ -66,15 +66,15 @@ struct ContentView_Previews: PreviewProvider {
     
     static var previews: some View {
         Group {
-            let doc = ChessDocument(mode: GameMode(value: .analyze))
+            let doc = try! ChessDocument(mode: GameMode(value: .analyze))
             ContentView(document: .constant(doc))
         }
         Group {
-            let doc = ChessDocument(mode: GameMode(value: .train))
+            let doc = try! ChessDocument(mode: GameMode(value: .train))
             ContentView(document: .constant(doc))
         }
         Group {
-            let doc = ChessDocument(rotated: true)
+            let doc = try! ChessDocument(rotated: true)
             ContentView(document: .constant(doc))
         }
     }
diff --git a/Shared/Views/InformationView.swift b/Shared/Views/InformationView.swift
index a458f52..78afb32 100644
--- a/Shared/Views/InformationView.swift
+++ b/Shared/Views/InformationView.swift
@@ -100,11 +100,11 @@ struct InformationView: View {
 struct BottomInformationView_Previews: PreviewProvider {
     static var previews: some View {
         Group {
-            let doc = ChessDocument(pgn: "1. e4 e5 *")
+            let doc = try! ChessDocument(pgn: "1. e4 e5 *")
             InformationView(document: .constant(doc))
         }
         Group {
-            let doc = ChessDocument(pgn: "1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nc3 dxe5 *")
+            let doc = try! ChessDocument(pgn: "1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nc3 dxe5 *")
             InformationView(document: .constant(doc))
         }
     }
diff --git a/Shared/Views/LabelsView.swift b/Shared/Views/LabelsView.swift
index ad1102e..10fac89 100644
--- a/Shared/Views/LabelsView.swift
+++ b/Shared/Views/LabelsView.swift
@@ -51,14 +51,14 @@ struct LabelsView: View {
 struct LabelsView_Previews: PreviewProvider {
     static var previews: some View {
         Group {
-            let doc = ChessDocument()
+            let doc = try! ChessDocument()
             ZStack {
                 BoardView(document: .constant(doc))
                 LabelsView(document: .constant(doc))
             }
         }
         Group {
-            let doc = ChessDocument(rotated: true)
+            let doc = try! ChessDocument(rotated: true)
             ZStack {
                 BoardView(document: .constant(doc))
                 LabelsView(document: .constant(doc))
diff --git a/Shared/Views/NavigationView.swift b/Shared/Views/NavigationView.swift
index 5988384..a4f2501 100644
--- a/Shared/Views/NavigationView.swift
+++ b/Shared/Views/NavigationView.swift
@@ -51,7 +51,7 @@ struct NavigationView: View {
 
 struct NavigationView_Previews: PreviewProvider {
     static var previews: some View {
-        let doc = ChessDocument()
+        let doc = try! ChessDocument()
         NavigationView(document: .constant(doc))
     }
 }
diff --git a/Shared/Views/NewGameView.swift b/Shared/Views/NewGameView.swift
index 47f476c..c5c90e3 100644
--- a/Shared/Views/NewGameView.swift
+++ b/Shared/Views/NewGameView.swift
@@ -84,11 +84,11 @@ struct NewGameView: View {
 struct NewGameView_Previews: PreviewProvider {
     static var previews: some View {
         Group {
-            let doc = ChessDocument()
+            let doc = try! ChessDocument()
             NewGameView(document: .constant(doc), editMode: false)
         }
         Group {
-            let doc = ChessDocument()
+            let doc = try! ChessDocument()
             NewGameView(document: .constant(doc), editMode: true)
         }
     }
diff --git a/Shared/Views/PiecesView.swift b/Shared/Views/PiecesView.swift
index d596703..a3fb127 100644
--- a/Shared/Views/PiecesView.swift
+++ b/Shared/Views/PiecesView.swift
@@ -165,14 +165,14 @@ struct PiecesView: View {
 struct PiecesView_Previews: PreviewProvider {
     static var previews: some View {
         Group {
-            let doc = ChessDocument()
+            let doc = try! ChessDocument()
             ZStack {
                 BoardView(document: .constant(doc))
                 PiecesView(document: .constant(doc))
             }
         }
         Group {
-            let doc = ChessDocument(rotated: true)
+            let doc = try! ChessDocument(rotated: true)
             ZStack {
                 BoardView(document: .constant(doc))
                 PiecesView(document: .constant(doc))
diff --git a/Shared/Views/TopInformationView.swift b/Shared/Views/TopInformationView.swift
index 72e0dc3..ecac8e8 100644
--- a/Shared/Views/TopInformationView.swift
+++ b/Shared/Views/TopInformationView.swift
@@ -99,15 +99,15 @@ struct TopInformationView: View {
 struct TopInformationView_Previews: PreviewProvider {
     static var previews: some View {
         Group {
-            let doc = ChessDocument(pgn: "1. e4 e5")
+            let doc = try! ChessDocument(pgn: "1. e4 e5")
             TopInformationView(document: .constant(doc))
         }
         Group {
-            let doc = ChessDocument(pgn: "1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nc3 dxe5 ")
+            let doc = try! ChessDocument(pgn: "1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nc3 dxe5 ")
             TopInformationView(document: .constant(doc))
         }
         Group {
-            let doc = ChessDocument(pgn: "1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nc3 dxe5 5. d4 exd4 6. Qxd4 Qxd4 7. Nd5 Nxd5 8. Bb5+ c6 9. Bxc6+ Nxc6 *")
+            let doc = try! ChessDocument(pgn: "1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nc3 dxe5 5. d4 exd4 6. Qxd4 Qxd4 7. Nd5 Nxd5 8. Bb5+ c6 9. Bxc6+ Nxc6 *")
             TopInformationView(document: .constant(doc))
         }
     }
diff --git a/Shared/Views/VariationSelectionView.swift b/Shared/Views/VariationSelectionView.swift
index 4c0632e..098d5f7 100644
--- a/Shared/Views/VariationSelectionView.swift
+++ b/Shared/Views/VariationSelectionView.swift
@@ -61,7 +61,7 @@ struct VariationSelectionView: View {
 struct VariationSelectionView_Previews: PreviewProvider {
     static var previews: some View {
         Group {
-            let doc = ChessDocument()
+            let doc = try! ChessDocument()
             ZStack {
                 BoardView(document: .constant(doc))
                 PiecesView(document: .constant(doc))